The United Nations Security Council on Friday voted to amend the mandate of a peacekeeping mission in South Sudan so it can back implementation of a recent peace deal, but Russia and Venezuela abstained over concerns about sanctions and surveillance drones.

A political row between South Sudan's President Salva Kiir and his former deputy Riek Machar sparked civil war in late 2013 and reopened ethnic fault lines between Kiir's Dinka and Machar's Nuer people. More than 10,000 people have been killed.

Kiir and Machar signed a peace deal in August, but since then both sides have accused one another of attacks, and humanitarian groups have pulled out of parts of the oil-rich country where heavy violence has been reported.

Some 13,000 U.N. peacekeepers are still sheltering more than 200,000 people at camps throughout South Sudan. Peacekeepers have been deployed in South Sudan since the country declared independence from Sudan in 2011.

"This resolution expresses our continued commitment to maintain pressure on both sides, neither of which has fully complied with its ceasefire obligations," U.S. deputy U.N. Ambassador David Pressman told the council.